Rectifier Diode Circuit Lab – Introduction
In both the Prelab and Lab, the two diode or resistor circuits were made according to the circuit diagrams. In the MultiSim and the Lab circuits, which were created on a breadboard Prelab circuits were replicated. For the voltage out of the circuit (Voutpk), and the voltage into the circuit (Vinpk) the measurement is done in each of the circuits and by using the oscilloscope it can be viewed. To demonstrate the characteristics and applications of the diodes in circuits is the purpose of the resistor; the properties of a rectifier diode are verified by the results.
The circuits that were used in the Prelab are shown in the figure Figures 1 &2. The table of data for Vinpk, Voutp and the MultiSim shows that the circuits were constructed in the Prelab. However, the waveforms for VinandVout oscilloscope waveforms were obtained. The circuits that were construct on the breadboard, or the table of data has the screen shots regarding to the oscilloscope waveforms, thus verify and reproduce results in the Prelab and Lab are shown in the Figures 3 & 4 show.
On the breadboard, the Lab Circuits 3 & 4 were construct and frequency shown in the corresponding Figures were according to the AC generator that was set for the sine-wave, at the voltage shown. However, with the Channel 1 scope probe on the DC coupling mode, oscilloscope was set, the generator leads to measure across the scope probe so that Vin., + and – peak voltages could be known, and through using a camera waveform was captured. Across the diode the Channel 1 scope probe was connected in order to know the Vout., + and – peak voltages, waveform etc.
Figure 1 – Pre Lab Circuit 1 Figure 2 – PreLab Circuit 2
Figure 3 –Lab Circuit 3 Figure 4 – Lab Circuit 4
For Figures 3 & 4 that are listed in Table 2 are used to obtain the values of Vin and Vout . Form Figure 3 the waveforms Vin and Vout are shown in the Figures 5 shows and from the Figure 4 the waveforms Vin and Vout are shown in the Figures 6.
In the proper direction example (+ to the anode, – to the cathlode), when the diode is biased the results could be shown and when the current will flow it reaches to junction potential, which the voltage across the diode and around 0.6 V for a silicon diode. There are two functions of diodes; they are either work in forwards direction or in reverse direction (- to the anode, + to the cathode), the diode when act in open circuit, there is no current flow. The source voltage was equal to the voltage across the diode.
Table 1. Prelab Circuit Results of Diode circuits
|PreLab Circuit Number||+VIN, peak |
|+VOUT, peak |
|-VIN, peak |
|-VOUT, peak |
Table 2. Lab Circuit Results of Diode circuits
|Lab Circuit Number||+VIN, peak |
|+VOUT, peak |
|-VIN, peak |
|-VOUT, peak |
Fig. 1 – Lab Circuit 1
Fig. 2– Lab Circuit 2
Discussion of the Results
According to the results, it I identified that there is a strong correlation between the Prelab results and the current lab results. According to the figure 3, the resistor is connected at the output voltage side of the circuit. The figure shows that, for the first half cycle of the input voltage, the diode is forward biased that it, it let the current flow in the circuit and for the others half cycle of the input voltage, the diode is reversed biased that is it do not allow current flows in the circuit. The output voltage shows the exact waveform as the input voltage for the positive half cycle at the R1. The peak output voltage for the given circuit is +Vin -0.6v.. The given case verifies the KVL rule that is VD+VR1=Vin.
The diode could be said as the reverse biased or an open circuit, on the negative ½ cycle of input voltage of the diodes. Across the open, circuit VD the applied voltage can be developed, when there is no flow of current in the circuit. However, through the resistor, the current is flow and across the resistor, no flow of current could be seen. Consequently, we can say that across the resistor no voltage was developed. .
Regarding the fig 4, for the output of the circuit, VD = Vout, the diode is connected. The diode is the reverse biased, for the positive of the ½ cycle of input voltage. The Vout waveform = the Vin waveform because the diode acts as the open circuit.
In the fig 5 and 6, however, in negative ½ cycle of input voltage the diode is forward biased. -0.6V (Vout) is the voltage across the diode, as shown in the Vin and Vout the functions are negative ½.